Bladed rotor for axial-flow fluid machine



4, L" HAWORTH v BLADED ROTOR FOR AXIAL-FLOW FLUID MACHINE Filed NOV. 28,1955 4 Sheets-Sheet l BLADED ROTOR FOR AXIAL-FLOW FLUID MACHINE FiledNov. 28, 1955 4 Sheets-Sheet 2 April 4, 1961 L. HAWORTH BLADED ROTOR FORAXIAL-FLOW FLUID MACHINE Filed Nov. 28, 1955 4 Sheets-Sheet 3 April 4,1961 L. HAWORTH 2,978,168

BLADED ROTOR FOR AXIAL-FLOW FLUID MACHINE Filed Nov. 28, 1955 4Sheets-Sheet 4 United States P a BLADED ROTOR FOR AXIAL-F LOW FLUIDMACHINE Lionel Haworth, Littleover, England, assignor to Rolls- RoyceLimited, Derby, England, a British company Filed Nov. 28, 1955, Ser. No.549,430

Claims priority, application Great Britain Dec. 6, 1954 6 Claims. (Cl.230-132 having pivoted blades are usually provided withradiallyextending peripheral flanges to'receive the blade-mounting pivotpins and the blades have lugs at'their root ends overlapping the.flanges'andalso receiving the pivot pins.

a It is often desirable to supply a fluid to the' bladessof anaxial-flow fluid machine; .for instance, in the case of the first-stageblading 'of an axial-flow compressorof an aircraft gas-turbine engine itis often desirable to supply a heating fluid to the blading for thepurpose of preventing or reducing ice formation on the blading.

This invention has for an object -to provide a rotor structure for anaxiaLflow fluid machine having pivoted blading and improved meanswhereby a fluid may be supplied to the pivoted blading.

According to the present invention, in a rotor of the type referred tothe inlet ends of fluid passages in the pivoted blades and fluid supplypassages in the rotor structure meet at positions offset from therespective pivot pins in surfaces of the blade roots and the rotorstructure which are urged into contact by loads experienced inoperation. j

According to a feature of the present inventiomwhere the blades arepivoted blades of the rotor of an axialflow compressor, the'inlet end ofafluid passage in each of a' plurality of the pivoted blades is'arranged 'to open to an upstream-facing surface of'the blade root, thesurface being at right angles to the pivotal" axis. of the blade and thepassage opening at a position in the root 'oflset from the bore for thepivot pin of't'he blade, an adjacent peripheral flange on the rotorstructure is provided with apertures in its downstream-facing surface tooverlap 'each of said inlets in the-blade roots, said downstream'surface also being at right angles to the pivotal axis, theupstreamfacing surface of the blade root being held against thedownstream-facing surface of the flange by the gas load on the blade,and there is provided an annular manifold as part of the rotor structureto supply fluid to.the apertures in the peripheral flange and thus tothe inlets in the blade roots.

, According to one preferred arrangement, an annular disc is secured tothe rotor structure, and the annular disc and the peripheral flange byhaving parts thereof in axial abutment form a manifoldspacel betweenthemf In such a construction it is preferredto arrange that the fluidcannot flow from the manifold through the apertures in the flange forthe pivot pins;" for instance the annular disc may be providedwithrecessed lands which abut the peripheral flange around the aperturesfor the pivot pins, so sealing them from the fluid space of themanifold.

2,978,165 Patented Apr. 4, 1961 In another preferred arrangement, a pairof annular discs are secured together to form a manifold space betweenthem, the fluid being fed to the space for distribution, the discs aremounted on the rotor structure in spaced relation to the peripheralflange which has the apertures overlapping the inlets in the blade rootsand transfer pieces are provided which flt in the apertures and inaligned apertures in one of the discs to convey the fluid from themanifold space to the peripheral flange and thus to the inlets in theblade roots.

Two embodiments of the invention as applied to an anti-icing apparatusfor pivoted blades of an axial-flow compressor of an aircraftgas-turbine engine will now be described. The description makesreference to the accompanying drawings in which:

Figure 1 is an axial section through part of the com- 'pressor,

Figure 2 is a similar view at an angularly spaced location,

Figure 3 is a section on the line III-HI of Figure 2,

Figure 4 is a view in the direction of arrow IV on Figure 1,- partsbeing broken away, and the section lines Figures 1 and 2 being indicatedat I1 and lI-II respectively, 25

Figures 5 and 6correspond to Figures 1 and 2 and show asecond-embodiment, Figure 7 is-an enlargement of part of Figure 6, andFigu'i-e 8 corresponds to Figure 4 and shows the section linesforFigures S'and oat VV and VI-VI respectiyely'."" I Referring toFigures 1 to 4 showing the firstembodiment, the rotor of the axial-flowcompressor comprises a central hollow shaft 10 on which there aremounted in axially-spaced relation a number of blade-carrying discs (notshown) for the rotor blades of the second and subsequent stages of thecompressor, and the peripheries of the discs are/held in spaced relationby spacer rings 11. The upstream end of the shaft 10 has secured to itan axial extension 13, and these parts abut over radial flanges 14, 15and the radial flanges support the disc 18 carrying the first-stagerotor blades. For this purpose the flange 15 on the shaft extension 13is axially thickened and is provided with a frusto-conical outwardflange 16 which is inclined'away from the flange 14 at the upstream endof the shaft 10 and terminates atits outer end in a radial portion 17.The disc 18 carrying the first-stage rotor blades 19 has anaxially-thickened portion 20 to abut the flange'15 of the shaftextension 13, afrusto -conical. portion'21' ext'ending outwards to anouter radial portion 22 whichiabuts' the outer radial portion 17 of theflange 16 and is secured to it. Bolts 23 extend through the thickenedportion 20 of the disc and the flange ,15 of the shaft extension 13 andthrough the radial flang'e 14 on the shaft 10. 'There is thus formed atriangular-section annular'space 24 which is used as a primary manifoldfor a hot air supply which is to be conveyed to drillings 25 in thefirst-stage blading 19.

The first stage blading 19 is pivoted to the rim 26 of the disc 18 therim having a number of radial flanges 27 and the rotor b'lading 19having corresponding lugs 28 on its root portion, the lugs 28 beingintercalated with the flanges 27, and the lugs and flanges having pivotpins 29 extending substantially axially through them. The flanges 27 andlugs 28 have their contacting surfaces at right angles to the axes ofthe pivot pins 29.

The hot air is conveyed to the primary manifold 24 from any convenientsource, such as the delivery of the compressor, through stationarystructure whence it passes in a generally radial direction through slots20a in the thickened portion 20 of disc 18.

" The hot-air is conveyed from the primary manifold essence 24 to adistributing manifold which is formed by attach ing an annular disc 30to the blade-carrying disc 18.

The manifold-forming disc 30 has at its inner radius a radial portion 31which abuts the radial portion. 22 on the blade-carrying disc 18, andthe bolts 32 which hold the manifold-forming disc 30 in position arethose which extend through the outer radial portions 22, 17 of theblade-carrying disc 18, and the shaft extension 13. The manifold-formingdisc 30 has an axial portion 33 extending from the outer radius of theradial por tion 31 and at the end of the axial portion a further radialportion 34 which extends outwardly into contact with a short axialflange 35 provided at the outer periphery of the upstream radial flange27. The axial portion 33 is sufliciently flexible for the centrifugalloads experienced in operation to cause a good seal to be maintainedbetween the manifold-forming disc 30 and the short axial flange 35.

The inner radial portion 31 of the manifold disc 30 has a number ofradial channels 36 cut in it between its bolt holes, the channelsstopping short of its inner periphery, and drillings 37 are formed inthe bladecarrying disc 18 to connect the channels 36 with the interiorof the triangular-section primary manifold 24.

The fluid flows from the primary manifold 24 through the drillings 37and the channels 36 into a space 38 between the inner surface of theblade-carryingdisc rim 26, and theaxialportion 33 and inner part of thesecpnd radial portion 34 of the manifold-formingdisc 30. The wan a swm-44 .31 n f q min gd 30 ha's a gihmber of lands -39 "extending axiallyf from it, the number spacing of thelarids lgeing -e'g fiiahtp thenumber andspacing of the'piv ot pins 29. EachEla nd aszts s ints s amant t s smit ei i s a is fla e 27.9 2 maq 'sfie 2 a a'central cavity 4t(Figure 2) ,into which-the 'ehd .bf

thejassofciat d pivot the fpivdtpin-receiVi'ng holes in the upstreamradial flange-27 are sealed 01f fr'om 't'he fluidjnianifold 38. Theupstream radial flange 27 is "formed with a number Tof holes 41 (Figures1 and 4) which extendto its downstream surface to aflord'the outletsfrom the manifold. These holes are assertion; the pivsrpin'hales "in theflange 21.

Each of the first-stage'rotorblades'has its drilling 25runningflengthwisjeth'ereof adjacent iis le'adirig edge and the drillingextends into '.the rderponi n 'to terminate radially outside thepiu'otpin hols in the lugs 2 8 and there 'is a short "axially-extending'drillin'g 142 'to "the lower e'rid er the "main'drilli'rig 2s 'ffdm a'point in the upstream face of'the upstream lug 28'50 dimensioned andarranged as to "overlap the' correspondiri-g'outlt hole 'ferred into the'pas's'ag'es'in the blades 19, regardls's' fof the"angularpbsitionof theblades about'theirfpivot axes at any given'in'stant'in operation. v H

The upstream-face of'tlie upstream lu'gZS o'ft he blade and thedownstream face of the upstream radial flange 27 'are, as'statedabovefmadesquare'withthe axisoftlie associated pivot'pin 29.'No'w, although there 'willbea small axialcleara'nce 'between'the radialflanges 27' on the disc rim 26 and the lugs '28 onthe"rotor blades 19through whichthe fluid might leak, theresultant'force acting-axially onthe blades 19 due to the pressure rise across them willurge the squaredsurfaces intocontact to give a'true face joint which does not preventpivot- -ing of the blades-19 whilst-substantially"avoiding fluiddisturbance, thereby tending to blow the lug and flange apart, a smallgroove 44 (Figures 1 and 4) is formed in the upstream face of the lugaround the opening of the drilling 42, and the groove is placed incommunication with the space radially outside the disc rim. In this wayany leakage fluid may escape freely, and it is arranged that the area ofthe face around the drilling, within the groove, is such that the loadwhich may be applied to it by the pressure of the fluid is much lessthan the forward axial load on the blade.

In operation, when his desired to prevent or reduce ice formation on thefirst-stage rotor blading 19, hot

air is supplied to the triangular-section primary manifold 24, forexample from the delivery of a later stage-of the compressor, and itthen flows therefrom in the man ner described above into the spacebetween the upstream radial flange 27 and the manifold disc 30. The hotair then flows through the holes 41 in the upstream radial flange 27into the inlet drillings 42 in the blade roots and thus to the leadingedge drillings 25. -In thesecond embodiment (Figures 5 to 8), the compressor rotor comprises .a central-hollow shaft 50, and in this case allthe rotor discs 51, including that carrying the first-stage rotorblading, are splined on the shaft '50 with spacer rings 53 between'theirrims 54. The 'splined connection for the first-stage disc's! is shown:at -52.

V -In this construction, the first-stage'blade-carryingdisc ==51=has -anumber .ofradial flanges :55 on:its-rim.5-4=with sets of aligned'holes-in them itosreceiverpivotpins 56 tby fivhich tthenrotor bladingis connected to :the disc. eEach-d'otor blade :57 has lugs -58,-at -itsinner-end :which -arev intercalated with the n'adial-flanges 55 :on thedisc 1 -im, 54.and are ?'bored to receive {the associated pivot pin:-56, and moreover, the bladerris provided with :aljon- 'gitudinal(passageway :59 extending adjacent the --leading-cdgetrom its -:t ip -towithin the root-end ofthe ==blade-whereit is met'by a -drilling-60(Figure 7)from -the.-u pstream face of the upstreamlug 58'to.provide'a.n4.0 inlet to the passage 59. As 'in'thefprevious construction,the-upstream face-of the lug 58on the blade and the downstream face ofthe upstream radial flange 55 are arranged'to be-square with'the axis-of-the-pivot;pin 56, thus to make a truefacejo int. I Hot-.airis-fedto theinlet-drilling 60-in the-following The front end of the rotor shaft ismounted in-a bearing accommodated withina bearinghousing-fl which isformed witha. pair of radially-spaced annularflanges 50 62 which extendaxially from the bearing housing towards the first-stage blade-carryingdisc 51. A hot air supply passage 63 in the bearing housing leads to thespace between the two flanges. v I Co-operating withthe twolflanges 62are a pair of labyrinth seal members 64, of which member 64 is.formed-on-the blade-carrying-disc adjacent its centre and mgr-operates.with -the .innersurface of :the innermost of the;two-fianges-.62, .andmember 65 is formed at the inner periphery of a manifold-forming disc 66and co- 5" -operates-with the inner surface of the outermost flange 62.

iThemanifold-forming disc 66 is-secured by radiallys'p'acedsets'of bolts67 to the bIade-carrying-dis'c-SI on the upstream sidethereof, and theblade-carrying disc 65 -51 and the manifold forming 'disc 66 are formedwith abutting bosses 68, 69 where the bolts pass through them 'so thatthe greater part of these-discs are 'Spacedapart *arid the space 70between thediscs' communicates with thespace between'the tWo flanges'GZon thebea'rin'g hous- 7G ir'igtoreceive hot air'therefrom.

, Towards itsouter" dge'th'e manifold-forming disc 66 isifraiike d'in'section to follow the 'contour'of'the' blade- "carryin disc 1 'r-im'54 and to have an axially-extending portion71,1 which-is spaced radiallyinwards of'the inner surface of the-blade-carryingdisc rim-'54,'and aradial portion 72 which extends outwardly alongside the upstream radialflange 55 on the rim 54.

The manifold-forming disc 66 forms the upstream wall of the hot airdistribution manifold and the radial portion 72 has at its outer edge athickened bead 73 which projects towards the upstream radial flange 55.

A ring 74 having substantially the same radial extent as the radialportion 72 of the disc 66 is secured to the radial portion 72 to bebetween it and the radial flange 55. The ring 74 has an outer peripheralportion in contact with and welded to the head 73 and an innerperipheral portion 75 extending axially towards and into contact withthe radially inner edge of the blade-carrying disc rim 54.

The ring 74 is of corrugated form with the corrugations extendingradially and thus both surfaces of the ring 74 have a series ofcircumferentially-alternating lands and grooves which extend from itsinner edge to close to its outer edge. The lands 76 projecting from theupstream face of the ring abut and are welded to the downstream surfaceof the radial portion 72 of the manifold-forming disc 66, and theintermediate parts, which afford the grooves on the upstream face of thering 74, have adjacent their outer ends holes 77 (Figures 5, 6 and 7)which run through the ring to the downstream surface thereof, and soopen to the centres of the lands on the downstream surface of the ring.

A number of axially-bored generally cylindrical transfer pieces 78 areprovided which fit in the holes 77 in the ring 74 and in aligned holes79 in the radial flange 55, the transfer pieces 78 havingcircumferential flanges 80 adjacent their mid-length which limit theaxial travel of the pieces 78 by abutting the upstream face of theradial flange 55 or the downstream face of the ring 74.

The hot air flows outwards from space 70 into the spaces between thelands 76 and then flows through holes 77, transfer pieces 78 and holes79 into the inlet drillings I claim:

1. A rotor for an axial-flow fluid machine comprising rotor structure, aring of blades at the periphery of the rotor structure, each of saidblades having a root, pivot pins engaging said roots and said rotorstructure pivotally to connect the blades to the rotor structure so asto allow a limited pivotal movement of the blades relative to the rotorstructure, said roots having surfaces which are urged into contact withcorresponding surfaces of the rotor structure by loads experienced inoperation, said blades having internal fluid passages with inletsthereto opening in said surfaces of the roots at positions oflset fromthe respective pivot pins, and fluid supply means in the rotor structureleading to outlets in said corresponding surfaces of the rotorstructure, said outlets overlapping the inlets in the roots, whereby thefluid is transferred from said outlets to said inlets in the blade rootsacross surfaces maintained in contact by loads acting on the blades inoperation of the machine.

2. A rotor for an axial-flow compressor comprising rotor structurehaving a peripheral flange with a flat downstream-facing surface, therebeing pivot-pin-receiving holes in the peripheral flange, a ring ofblades at the periphery of the rotor structure, each of said bladeshaving a root with a pivot-pin-receiving hole therein, pivot pinsextending through the holes in said roots and said peripheral flange ofthe rotor structure pivotally to connect the blades to the rotorstructure and to allow a degree of free pivotal movement of the bladesrelative to the rotor structure, said roots having flat upstream facingsurfaces, both said downstream-facing surface of the peripheral flangeand said upstream-facing surfaces of the roots being at right angles tothe pivotal axes of the blades, and said surfaces being urged intocontact by loads experienced in operation, fluid passages in the bladeshaving inlets thereto opening through said up stream-facing surfaces ofthe roots at positions offset from the pivot-pin-receiving holestherein, apertures in said downstream-facing surface to overlap each ofsaid inlets in the roots, whereby theifluid is transferred from saidapertures to said inlets in the blade roots across surfaces maintainedin contact by loads acting on the blades in operation of the machine,and said rotor structure comprising annular fluid supply manifold meansconnected to supply fluid to the apertures in the peripheral flange andthus to the inlets in the blade roots.

3. A rotor as claimed in claim 2, wherein said manifold means comprisesa pair of annular discs secured together to define a manifold spacebetween them, the fluid being fed to the space for distribution, thediscs being mounted on the rotor structure in spaced relation to saidperipheral flange, and transfer pieces having bores therein which fit inthe apertures in the peripheral flange and in aligned apertures in oneof the annular discs, the bores serving to convey the fluid from themanifold space to the apertures in the peripheral flange and thus to theinlets in the blade roots.

4. A rotor as claimed in claim 3, wherein the annular discs are sealedtogether at their outer peripheries, and one of the annular discs is ofradially corrugated form to provide alternate lands and grooves, thelands being in contact with the other annular disc and the correspond- Iing grooves forming distributing spaces leading to the apertures in thedisc receiving the transfer pieces.

5. A rotor for an axial flow compressor comprising rotor structurehaving a peripheral flange with aflat downstream-facing surface, therebeing pivot-pin-receiving holes in the peripheral flange, a ring ofblades at the periphery of the rotor structure, each of said bladeshaving a root with a pivot-pin-receiving hole therein, pivot pinsextending through the holes in said roots and said peripheral flange ofthe rotor structure pivotally to com nect the blades to the rotorstructure and to allow a degree of free pivotal movement of the bladesrelative to the rotor structure, said roots having flat upstreamfacingsurfaces, both said downstream-facing surface of the peripheral flangeand said upstream-facing surfaces of the roots being at right angles tothe pivotal axes of the blades, and said surfaces being urged intocontact by loads experienced in operation, fluid passages in the bladeshaving inlets thereto opening through said upstream-facing surfaces ofthe roots at positions offset from the pivot-pin-receiving holestherein, apertures in said peripheral flange opening to saiddownstream-facing surface thereof, said apertures overlapping each ofsaid inlets in theroots, and an annular disc secured to the rotorstructure and co-operating with said peripheral flange to define a fluidmanifold space, said apertures communicating with the manifold space,whereby fluid is transferred from the manifold space through theapertures to the inlets in the blade roots across said surfaces whichare urged into contact by loads experienced in operation, the annulardisc having recessed lands projecting from it into abutment with theperipheral flange around the holes therein for the pivot pins so sealingthe holes from the manifold space.

6. A rotor for an axial-flow compressor comprising rotor structurehaving a peripheral flange with a flat downstream-facing surface, therebeing pivot-pin-receiving holes in the peripheral flange, a ring ofblades at the periphery of the rotor structure, each of said bladeshaving a root with a pivot-pin-receiving hole therein, pivot pinsextending through the holes in said roots and said peripheral flange ofthe rotor structure pivotally to connect the blades to the rotorstructure and to allow a degree of free pivotal movement of the bladesrelative to the rotor structure, said roots having flat upstreamfacingsurfaces, both said downstream-facing surface of the peripheral flangeand said upstream-facing surfaces or the roots being at right angles tothe pivotal axes of the blades, and said surfaces being urged intocontact by loads experienced in operation, fluid passages in the from1the pivot-pin-receiving holes :thenein,:=apertures in vsaid.downstream-facingsurface to overlap each of said .inlets in the roots,whereby the fluid is transferred from said apertures to said inlets inthe blade roots across surfaces maintained in contact by loadsacting..on the blades inoperation of themachine, and'said rotorstructure comprising a annular fluid supply manifold means connected tosupply fiuidto the apertures in the peripheral flange and thus to-the"inlets inthe blade roots, and the .upstream-facing surfaces of :theblade roots having each 1 a groove formedthereinaround the. inlet of therespective passage, the :grooves being ni -communication with-the spaceradially ouisidethe peripherallflange oftthe rotor.

, Reierences Cited in the. tile of; thisapatent UNITED STATES PATENTS2,568,726 :Franz ..:Sept. 25, 1951 2,599,470 -Meyen June:3, 619522,648,520 :;Schmitt rAug-:11,-:-1953 2,656,146 :-.Sollin ger-.-.Oct.-.20, 1953 2,675 ,208 Weinberg Apr.- 13,1954 2,727,716 FeildenDem--20, :1955 12,819,869 =Meyer. ...'J an. 11,4, :1958

